The present invention relates to the field of sling swivels for attaching a sling to a firearm and, in particular, to such swivels which quickly detach from a conventional mounting base on the firearm through manipulation of a depressible plunger.
A particular type of quick-detachable sling swivel, having a security feature, is described in Ives, U.S. Pat. No. 4,454,675. In its preferred embodiment, this swivel includes a main body, a loop portion carrying the sling, and a projecting pin that can be inserted into an opening formed in the mounting base of the firearm. To detach the swivel from the firearm, a gate operably mounted on the main body is selectively moved from its normal position surrounding the projecting end of the pin to an open position clearing the pin so that the pin is removable from the base. More particularly, a rear portion of a spring-biased plunger, extending outwardly from a central bore in the main body, operates the gate, which is joined to a forward end of the plunger. To secure or lock the swivel to the firearm, the rear portion of the plunger is externally threaded and a hollow internally-threaded mating sleeve is rotatably movable to an activated position therealong, so that despite depression of the plunger the gate is unable to shift sufficiently to clear the end of the pin.
In the security-type swivel described above, however, if the threaded sleeve element is not screwed tightly enough into its activated position, it might become loosened and be turned incrementally down a sufficient length of the rear portion of the plunger to permit the plunger to be depressed far enough to enable the swivel to be detached from the firearm unintentionally.
During manufacturing, to assembly the described security-type swivel, it is first necessary to screw the threaded sleeve along some preliminary length of the rear portion of the plunger, so that upon insertion of the plunger through the central bore, the forward end of the plunger will project sufficiently from the bore to allow attachment of the gate. The screwing operation involved requires repeated turning movement of the threaded sleeve element on the rear portion of the plunger and is a labor-intensive task that increases manufacturing expense for each unit.
Accordingly, it is an object of the present invention to provide a quick-detachable security-type sling swivel which can be inexpensively assembly without performing labor-intensive screwing-type operations.
A further object of the present invention is to provide a quick-detachable sling swivel which has a secure configuration for preventing accidental detachment of the swivel from the firearm and which includes a mechanism for preventing unintentional removal from the secure configuration.